Event.explicitOriginalTarget

Non-standard
This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

Summary

The explicit original target of the event. (Mozilla-specific)

If the event was retargeted for some reason other than an anonymous boundary crossing, this will be set to the target before the retargeting occurs. For example, mouse events are retargeted to their parent node when they happen over text nodes (see bug 185889), and in that case currentTarget will show the parent and explicitOriginalTarget will show the text node.